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Some watches are defined by who wore them, and this is certainly the case for the Universal Geneve Tri-Compax “Eric Clapton”. His taste of watch straps may be disputable, but I remember having one of those in the early 70s as well 😉

The watch itself is of undisputed taste, and there is also a version with a dark dial with white sub-dials, referred to as the “Evil Clapton” version.

These beasts are rare enough, and even rarer when in good condition, as this one, which was sent in by a customer from Florida.

Unfortunately, the watch isn’t working, so we’ll have to find out what’s ailing it.

The UG 281 tri-compax movement is not only a chronograph movement with a minute and hour recorder, but it also has a dial for the date, a day disc, a month disc and a moon phase indication. To complete it, there is also a sub-second indication.

The dial is in mint condition, with the luminous compound original and undamaged.

The back of the dial looks as it should.

The bottom plate shows some of the complexity of the movement. The month indication isn’t automatic, e.g. you have to manually advance the month yourself. Slightly useless, but the month indication helps the symmetry of the dial.

The top plate hosts the chronograph with second and minute recorder.

The movement is in almost pristine condition, with a very nice balance and hairspring with Breguet overcoil.

And here is the culprit – the click spring is broken, and that’s why the watch couldn’t be wound any more.

All parts cleaned and ready for re-assembly.

The click spring I found on eBay has been previously repaired, but as long as it works correctly, I’m not going to be picky. It was hard enough to find one in the first place.

The click spring in place and working.

The barrel gets a new mainspring.

The gear train put into place.

A very nice performance from the start.

Now I put the chronograph layer on.

And then turn my attention to the bottom plate.

The hour recorder and its brake at 6 o’clock.

The movement is back together, and when testing, I find that the date hand doesn’t advance reliably.

The culprit is the tooth on the date star driving wheel (the wheel next to SAT). It has shortened teeth, but one that’s a bit longer which advances the date star wheel once every turn. Not only is the tooth too short, but the date star wheel also isn’t aligned properly. This way, even with a new driving wheel, I will either advance two days at a time, or none.

The jumper spring that determines the position of the wheel needs to be modified a bit to turn the wheel by half a tooth.

You can see that I took of a bit off the top of the jumper spring.Now the date star tooth points directly to the centre of the date star driving wheel, assuring that it will be advanced by exactly one tooth per day.

The quick-set lever for the date also needs some modification as it’s not advancing reliably.

The new date star driving wheel on the left, and the old one on the right. You can see that the tooth on the left wheel is a bit longer.

Now the date advances reliably by one tooth per day.

The date wheel is below the moon phase wheel.

The dial and hands are on, and everything works as it should.

The movement is cased again, and I can proceed to the final testing.

A very nice watch with a very nice dial.

Some of you will have noticed the tachymetre bezel – it looks almost exactly like a Speedmaster tachymetre bezel ring, but the diameter is different, so they aren’t interchangeable.

A beautiful watch, and not easy to get hold of in good condition, so I’m very envious, and first on the list should it ever be sold 😉